The present invention relates generally to the switching of the data packets in each switching node of a data transmission network supporting the Internet Protocol (IP) and particularly to a method of self-learning for the switching nodes of such a data transmission network.
Today""s data communications and networks would not exist without routers. Routers are essential to link Local Area Networks (LAN) and remote sites. The xe2x80x9croutingxe2x80x9d function involves two basic activities: determination of routing paths and the transport of information packets or frames through the network referred as the xe2x80x9cswitchingxe2x80x9d function. Path determination may be based on a variety of metrics which are values resulting from algorithmic computations. Software implementations of routing algorithms calculate route metrics to determine optimal routes to a destination. To aid the process of path determination, routing algorithms initialize and maintain routing tables which contain route information depending on the routing algorithm used.
Since routing is considered to be one of the major bottlenecks in networks within the past few years, routers have become less central of building networks and being replaced by switches. The current trend is xe2x80x9cswitch when you can, route when you mustxe2x80x9d. In fact, it is easier to setup and maintain switches than routers insofar as switching algorithms are relatively simple and are basically the same for many routing protocols.
Integrating the functions of routing and switching in one product can improve network performance and achieve easy-to-manage administration. Such a switching node integrating the routing function is often called an IP switch in an IP data transmission network. In spite of the integration of the two functions, such an IP switch uses nevertheless a protocol, proprietary of course, between the routing part and the switching part of the switching node.
The drawback of an integrated switching node is the dependency on a limited number of IP switch manufacturers. The skills and expenses required to build a very efficient router requiring a lot of software with regular updates, and complex and sophisticated hardware for the switching system, are available only in a limited number of companies which have thus acquired a kind of monopoly on such products.
An alternate system is to interface the IP switch with the router by using a dedicated protocol such as General Switch Management Protocol (GSMP) proposed by Ipsilon Company. The drawback in this solution is first to find a router manufacturer offering this interface inasmuch as large router manufacturers prefer to build IP switches integrating the routing function. Then, it is necessary to implement this protocol which requires a complex development. The last drawback but not the least is the risk that as long as it is not a standard, such a specific protocol be withdrawn by the limited number of companies marketing it.
Accordingly, it is an object of the invention to provide an IP switch using a separated legacy router and without requiring the implementation of a specific protocol between the switch and the router.
Another object of the invention is to achieve a method of learning for a switching node using a separated legacy router such that the router is released of the switching tasks after the first frame of a flow has been transmitted by the switching node.